1. Technical Field
The present invention relates to an electronically powered cooling and heating device. More particularly, the present invention relates to an electronically powered cooling and heating device employing thermoelectric modules.
2. Description of Related Art
In the production of automobiles, passenger comfort has been and is a highly valued design component. One element in providing passenger comfort is the control of the environmental conditions in the passenger compartment. To control the temperature, air conditioners and heaters are considered standard equipment capable of fulfilling such need. Until now, automobiles have principally relied on essentially the same technology for interior temperature control. The heater utilizes the heat produced by the internal combustion engine of the vehicle to provide heat to the passenger compartment. The air conditioner operation utilizes a refrigeration cycle wherein a refrigerant, such as chlorofluorocarbons, are used to produce chilled air.
The concept and design of an automobile heater is simple. When the heater is activated, air is drawn through tubing surrounding the engine block. Ambient air is drawn from outside the vehicle and is conveyed passed the engine block where the cooler air absorbs heat. The now heated air is then supplied into the passenger compartment as desired. But this traditional design is problematic under different conditions: the temperature of the vehicle's engine is too low;
1) the intake (outdoor) air is too cold; or
2) the engine is not using internal combustion.
The two former situations arise in cold environments: the engine is cold or the outdoor air is too cold to be adequately warmed. However, these scenarios are when an effective heater is extremely important to the passenger. The latter situation arises more often today, as technology leads to alternatives to internal combustion engines.
In recent years, automobile manufacturers have seen a growing demand for alternatives to the traditional internal combustion-driven automobiles. Rising fuel prices, tensions in the oil-producing countries and a growing concern for the environment have stimulated the demand. Automobile manufacturers have responded by producing electric vehicles and hybrid-electric vehicles. As engines become more efficient, less energy is wasted in the form of heat. Traditional heaters may not be practical in these vehicles because they cannot utilize the heat that is expended from traditional internal combustion engines. While the traditional automobile heater may be imperfect, the automobile air conditioner presents even greater need for improvement.
A majority of vehicles produced today are equipped with air conditioning systems. Although there are different types, the concept and design are essentially the same. A belt driven pump is fastened to the engine. By increasing the drag on the engine, the pump drives the condenser. The condenser compresses refrigerant gas into a liquid state whereby heat is produced due to the heat of condensation which is expelled to the atmosphere outside of the vehicle. The refrigerant is then allowed to evaporate whereby heat is absorbed from air being conveyed passed coils. This cool air is conveyed into the passenger compartment to provide a cooled passenger compartment. Although air conditioners have improved over the years, automobile air conditioners still present many problems.
Even the most advanced air conditioners are bulky systems that require a myriad of rotating parts and operate under high-pressure. The belt-driven design requires that they be mounted in close proximity to the engine. And the condenser must be situated to permit allow air from the engine fan and forced air from the movement of the car to flow past it. Moreover, no matter how well an air conditioner is maintained, eventually it will present problems and require repair. Mechanical problems occur as the belts transfer torque. And the hoses, tubing and fittings that operate under high pressure will gradually wear and/or corrode. A failure of any part of the system will cause the entire system to languish. However, the most common and most significant problems are associated with the requirement of refrigerant gases.
Traditional automobile air conditioners commonly use an air conditioning unit employing refrigerant gas such as FREON (FREON is the trade name for the refrigerant R-12, that was manufactured by DuPont) or other chlorofluorocarbons (CFC's) or hydrochlorofluorocarbons (HCFC's). An adequate amount of the refrigerant gas is essential to produce temperature change as it is pumped through the condenser. As refrigeration units operate under pressure, these systems must be maintained by effective sets of seals to prevent leakage. And like other refrigerants, FREON is an odorless, colorless gas, making leaks difficult to find and repair. Most people will not recognize a problem with their air conditioner until much of the refrigerant has already escaped into the atmosphere. Not only do leaks of chlorofluorocarbons lead to expensive repairs, they cause great damage to the Earth's environment.
The release of FREON and other CFC's or HCFC's into the atmosphere has been blamed for the decay of the Earth's ozone layer. When ultraviolet light waves from the sun strike CFC or HCFC molecules in the upper atmosphere, a carbon-chlorine bond may break. A chlorine atom forms and then may react with ozone (O3) molecules to yield oxygen (O2) and chlorine monoxide (Cl-0). Then a free oxygen atom causes the chlorine monoxide molecule to purge the chlorine atom to form oxygen (O2). This chlorine is free to repeat the process in a vicious cycle. For example, each FREON molecule in the atmosphere is estimated to have an average life of 120 years and can destroy 100,000 ozone molecules or more. Thus a CFC molecule released in 2004 will still be damaging the ozone layer in 2114. The known effects of ozone depletion are numerous.
As the stratospheric ozone layer is depleted, higher UV-b levels reach the earth's surface. Increased UV-b can lead to more cases of skin cancer, cataracts, and impaired immune systems. Many of our essential crops, such as corn, barley, hops, wheat and soybeans, may become damaged, decreasing their yield. Phytoplankton, a plant in the ocean, also is affected. Depletion of this important link in the marine food chain could reduce the number of fish in the ocean. It also can increase the level of carbon dioxide in the atmosphere because phytoplankton absorbs carbon dioxide in their food and energy making processes.
However, much of the FREON that is produced will escape into the environment even with careful use. Moreover, regulations lead to greater costs to the consumer. The best solution lies in technology that replaces traditional air conditioners, thus eliminating the need for and production of FREON. While other refrigerants may be less harmful to the environment than FREON, substitute CFC's and HCFC's do still degrade the ozone layer.
What is needed is an improved cooling and heating device that would eliminate the need for CFC's or HCFC's. This would curb the production of CFC's and the like and ultimately reduce the amount that is released into the atmosphere, preventing ozone depletion, global warming and pollution. Also, a device that provides a simplified design with fewer moving parts will permit greater dependability and reduce the costs of installation, repair and service. Such a system should be able to operate without the requirement of torque generated by an engine, unlike traditional belt-driven units that must be attached or mounted next to the engine. A further quality desired would be that the device work interchangeably as both a heater and air conditioner, thus permitting the consumer to get heated air as well as cooled air. Thus, a device that provides greater versatility, permits the device to be produced in a small, compact size thus being suitable for use as a portable air conditioner/heater as well as an automobile air conditioner/heater would be desirable.